Thermal Management System

Abstract

To improve heat efficiency by a heating part, prevent a crack from being generated in the heating part due to air bubbles, and prevent a pump from being locked or emitting noise due to air bubbles.SOLUTION: A heat management system for managing heat of a heat medium circulating through a heat circuit 2 includes: a reservoir tank 3 for temporarily storing a heat medium; a heating part 4 for electrically heating the heat medium to the boiling point thereof; a heater core 5 for exchanging heat of the heated heat medium with the outside; and a pump 6 for pumping the heat medium. The heating part 4 is provided with air bubble discharge means for separating air bubbles contained in the heat medium from the heat medium and discharging the air bubbles and further includes air bubble recovery means for recovering the air bubbles discharged from the heating part 4.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a thermal management system used for heating the passenger compartment of an electric vehicle. [Background technology]

[0002] Conventionally, one known example of this type of technology is described in Patent Document 1 below. This technology is a thermal management system that manages the heat of a heat-generating element that generates heat through charging / discharging or power conversion, and includes a liquid heat transport medium (heat medium) that transports heat received from the heat-generating element, and a circuit (thermal circuit) through which the heat medium flows. The thermal circuit includes a heat-receiving section (heating section) that receives heat from the heat-generating element, a pump that pumps the heat medium, a heat exchanger that releases heat from the heat medium to the outside of the thermal circuit by heat exchange between the heat medium and a heat exchange medium, and a reservoir tank that stores the heat medium, all arranged in series. In addition, a removal section is provided in a part of the thermal circuit that removes gas generated from the heat medium to the outside of the thermal circuit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-107442 Summary of the Invention [Problem to be solved by the invention]

[0004] When considering a highly efficient heating section for the thermal management system described in Patent Document 1, it is possible to adopt a technology that boils the heat transfer medium to achieve a high heat flow rate. However, when using this type of technology, boiling the heat transfer medium generates bubbles. If these bubbles are not treated, they may accumulate in the heating section, causing hot spots and cracks, or they may enter the pump, causing it to lock or make abnormal noise. In this system, the bubbles can be discharged to the outside through the extraction section, but discharging the bubbles to the outside will gradually reduce the heat transfer medium, which could reduce the thermal efficiency of the system.

[0005] This disclosed technology has been made in consideration of the above circumstances, and its purpose is to provide a thermal management system that improves the thermal efficiency of the heating section and can prevent cracks in the heating section caused by air bubbles, and prevents the pump from locking or making abnormal noises caused by air bubbles. [Means for solving the problem]

[0006] In order to achieve the above object, the technology described in claim 1 is a thermal management system that is mounted on an electric vehicle and manages the heat of a heat medium circulating in a thermal circuit, and is equipped with a reservoir tank for temporarily storing the heat medium, a heating unit for electrically heating the heat medium to its boiling point, a heat exchanger for exchanging heat from the heated heat medium with the outside, and a pump for pressurizing the heat medium, wherein the heating unit is provided with bubble discharge means for separating and discharging bubbles in the heat medium from the heat medium, and bubble recovery means for recovering the bubbles discharged from the heating unit.

[0007] According to the configuration of the above technology, bubbles are generated in the heat medium when the heat medium is electrically heated to its boiling point by the heating unit. The heating unit is provided with a bubble discharge means for separating and discharging bubbles in the heat medium from the heat medium. The boiled heat medium flows downstream of the heat medium, and the bubbles in the heat medium are separated from the heat medium, discharged from the heating unit, and collected in the bubble recovery means. Therefore, the heat medium is heated to its boiling point, improving the heat flux of the heat medium. Furthermore, even if the heat medium boils in the heating unit, the heat medium does not contain bubbles and flows through the thermal circuit.

[0008] In order to achieve the above object, the technology described in claim 2 is the technology described in claim 1, in which the bubble discharge means has a structure that causes a spiral flow in the heating medium in a specific direction in the heating section.

[0009] According to the configuration of the above technology, in addition to the effect of the technology described in claim 1, a spiral flow in a specific direction is generated in the heating medium in the heating section, which makes it easier to separate bubbles from the heating medium.

[0010] In order to achieve the above object, the technology described in claim 3 is the technology described in claim 1 or 2, in which the bubble collection means includes a reservoir tank and a bubble piping for flowing bubbles from the heating section to the reservoir tank.

[0011] According to the configuration of the above technology, in addition to the effect of the technology described in claim 1 or 2, the bubbles discharged from the heating section flow through the bubble piping and are collected in the reservoir tank, so that the heat transfer medium that constitutes the bubbles can be liquefied in the reservoir tank. [Effects of the Invention]

[0012] According to the technology described in claim 1, it is possible to improve the thermal efficiency of the heating unit, prevent cracks in the heating unit due to air bubbles, and prevent locking or abnormal noise in the pump due to air bubbles. Also, it is possible to achieve highly efficient heat exchange of the heat medium in the heat exchanger.

[0013] According to the technology recited in claim 2, in addition to the effect of the technology recited in claim 1, it is possible to efficiently separate bubbles from the heat medium boiling in the heating section.

[0014] According to the technology recited in claim 3, in addition to the effect of the technology recited in claim 1 or 2, the heat medium liquefied in the reservoir tank can be reused in the heat circuit. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic diagram showing a heating device mounted on an electric vehicle according to an embodiment; [Figure 2] FIG. 3 is a vertical cross-sectional view showing the internal structure of a heating unit in one embodiment. [Figure 3] FIG. 3 is a plan view showing a heating unit according to one embodiment. [Figure 4] 3 is a cross-sectional view taken along line AA in FIG. 2 showing a heating unit according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment in which the thermal management system is embodied in a heating device for an electric vehicle will be described in detail with reference to the drawings.

[0017] [About heating equipment] Figure 1 shows a schematic diagram of a heating device 1 mounted on an electric vehicle (not shown). This heating device 1 constitutes a thermal management system that manages the heat of a heat medium circulating in a thermal circuit 2. The heating device 1 includes a reservoir tank 3 for temporarily storing the heat medium, a heating unit 4 for electrically heating the heat medium to its boiling point, a heater core 5 for exchanging heat from the heated heat medium with the outside, and an electric pump 6 for pumping the heat medium, all of which are arranged in series in the thermal circuit 2.

[0018] The reservoir tank 3 has a bottom that serves as a storage section for storing a liquid heat medium and a space above it. The heater core 5 has a number of fins around the pipe through which the heat medium flows, and is configured to exchange heat between the heat medium and the outside air. The heater core 5 corresponds to an example of a "heat exchanger" in this disclosed technology. An electric blower fan 7 is provided near the rear of the heater core 5, and this fan 7 blows air toward the heater core 5, thereby sending the air heated by the heater core 5 into the vehicle interior as warm air.

[0019] In the thermal circuit 2, the heat medium discharged from the pump 6 is heated in the heating unit 4 and flows to the heater core 5, where it is heat exchanged, and then returns to the pump 6 via the reservoir tank 3. The heat medium circulates through the thermal circuit 2 in this order.

[0020] Here, the heating unit 4 is provided with a "bubble discharge means" for discharging bubbles in the heat medium. Furthermore, the heating device 1 is provided with a "bubble recovery means" for recovering the bubbles discharged from the heating unit 4.

[0021] [About the heating section] Figure 2 shows a vertical cross-sectional view of the internal structure of the heating unit 4. Figure 2 is a cross-sectional view of the heating unit 4 taken along line BB in Figure 3, which will be described later. Figure 3 shows a plan view of the heating unit 4. Figure 4 shows a cross-sectional view of the heating unit 4 taken along line AA in Figure 2. The heating unit 4 includes a casing 11. The casing 11 includes a cylindrical chamber 12 into which a heat medium is introduced, and a small-diameter heat medium flow path 14 that is arranged parallel to the chamber 12 and communicates with the chamber 12 via a communication path 13 at the top of the casing 11.

[0022] The heating unit 4 further includes a high-voltage heater 15 that electrically heats the heat medium to its boiling point. Specifically, the chamber 12 houses a cylindrical high-voltage heater 15 to which a high voltage (e.g., 350 V) is applied. The high-voltage heater 15 heats and boils the heat medium introduced into the chamber 12. Boiling the heat medium generates bubbles from the heat medium. A cylindrical bubble discharge pipe 16 for discharging the bubbles is provided at the center of the upper part of the chamber 12. The casing 11 is also provided with an inlet joint 17 on its lower outer periphery for introducing the heat medium into the chamber 12. The casing 11 is also provided with an outlet joint 18 on its bottom surface for discharging the heat medium from the heat medium flow path 14. The inlet joint 17 is connected to the discharge port of the pump 6 via piping that constitutes the thermal circuit 2, and the outlet joint 18 is connected to the heater core 5 via piping that also constitutes the thermal circuit 2.

[0023] [Method for discharging air bubbles] Here, as shown in FIG. 4 , the inlet joint 17 is disposed in a cylindrical tangential direction of the chamber 12 when viewed from the bottom of the casing 11. When the heat medium is introduced into the chamber 12 from the inlet joint 17, the heat medium begins to swirl along the inner circumferential surface of the chamber 12, and as shown in FIGS. 2 and 4 , a spiral flow (indicated by arrows in the figures) is generated in the heat medium. Here, bubbles (steam bubbles) are generated from the heat medium that has been boiled by heating with the high-voltage heater 15, and the bubbles rise toward the upper direction (specific direction) of the chamber 12 due to the spiral flow of the heat medium and are introduced into the bubble discharge pipe 16. In this embodiment, the inlet joint 17, which generates this spiral flow, the chamber 12, and the bubble discharge pipe 16 constitute an example of the "bubble discharge means" of the disclosed technology.

[0024] Therefore, when the pump 6 in the thermal circuit 2 is operated, the heat transfer medium is discharged from the pump 6 and flows into the heating unit 4. The heat transfer medium is then introduced into the chamber 12 through the inlet joint 17. The introduction pressure of the heat transfer medium can be assumed to be 100 kPa. The heat transfer medium is introduced into the chamber 12 through the inlet joint 17 in a cylindrical tangential direction relative to the casing 11, generating a spiral flow along the inner circumferential surface of the chamber 12. This separates the vapor bubbles (gas bubbles) generated by the heating of the high-voltage heater 15 from the liquid (heat transfer medium). The low-density bubbles move toward the center of the chamber 12, while the high-density heat transfer medium moves toward the outside of the chamber 12 due to centrifugal force. Both the bubbles and the heat transfer medium then rise upward in the chamber 12 due to the spiral flow. Only the bubbles are then discharged from the casing 11 through the bubble discharge pipe 16. The bubble discharge pressure can be assumed to be 90 kPa. The spirally swirling heat medium flows through the communication passage 13 into the heat medium flow passage 14 and is discharged from the outlet joint 18 to the outside of the casing 11. The discharge pressure of the heat medium at this time can be assumed to be "10 (kPa)".

[0025] [Air bubble collection method] As shown in FIG. 1, a bubble pipe 19 is provided between the heating unit 4 and the reservoir tank 3 to allow bubbles to flow from the heating unit 4 to the reservoir tank 3. One end of the bubble pipe 19 is connected to the bubble discharge pipe 16 described above, and the other end of the bubble pipe 19 is connected to the reservoir tank 3. The bubbles discharged from the heating unit 4 to the outside are collected in the reservoir tank 3 via the bubble pipe 19. In the reservoir tank 3, the bubbles dissolve, and the components of the heat medium that made up the bubbles return to a liquid heat medium, which then flows again through the thermal circuit 2. In this embodiment, the bubble pipe 19 and the reservoir tank 3 constitute an example of the "bubble collection means" of the disclosed technology.

[0026] [About the operation and effects of heating equipment] According to the configuration of the heating device 1 of this embodiment described above, the heat medium is electrically heated to its boiling point by the heating unit 4, generating bubbles in the heat medium. The heating unit 4 is provided with a bubble discharge means for separating and discharging bubbles from the heat medium. The boiled heat medium flows downstream, while the bubbles are separated from the heat medium, discharged from the heating unit 4, and collected by the bubble recovery means. This improves the heat flux of the heat medium because the heat medium is heated to its boiling point. Even if the heat medium boils in the heating unit 4, bubbles-free heat medium flows through the thermal circuit 2. This improves the thermal efficiency of the heating unit 4 and prevents cracks in the heating unit 4 and locking or abnormal noise in the pump 6 due to bubbles. Furthermore, the heater core 5 achieves highly efficient heat exchange of the heat medium.

[0027] According to the configuration of this embodiment, an upward spiral flow (specific direction) is generated in the heat medium in the heating unit 4, which facilitates separation of bubbles from the heat medium. Therefore, bubbles can be efficiently separated from the boiling heat medium in the heating unit 4.

[0028] According to the configuration of this embodiment, the bubbles discharged from the heating unit 4 flow through the bubble piping 19 and are collected in the reservoir tank 3, so that the heat medium constituting the bubbles can be liquefied in the reservoir tank 3. Therefore, the heat medium liquefied in the reservoir tank 3 can be reused in the thermal circuit 2.

[0029] [Another embodiment] The disclosed technology is not limited to the above-described embodiment, and part of the configuration can be appropriately modified within the scope of the disclosed technology.

[0030] (1) In the above embodiment, the bubble discharge means is configured to introduce the heat transfer medium into the chamber 12 from the cylindrical tangential direction of the casing 11 through the inlet joint 17, thereby generating a spiral flow along the inner circumferential surface of the chamber 12. However, it is also possible to provide a rotating blade in the chamber to impart a spiral flow to the heat transfer medium.

[0031] (2) In the above embodiment, the reservoir tank 3 is used as a component of the air bubble collecting means, but a dedicated tank may be provided separately from the reservoir tank. [Industrial Applicability]

[0032] The disclosed technology can be used in heating devices for electric vehicles. [Explanation of symbols]

[0033] 1. Heating equipment 2 Thermal circuit 3 Reservoir tank (air bubble collection means) 4 Heating section 5 Heater core (heat exchanger) 6. Pump 12 Chamber (air bubble discharge means) 15 High voltage heater 16 Bubble discharge pipe (bubble discharge means) 17 Inlet fitting (air bubble discharge means) 19 Bubble piping (bubble collection means)

Claims

1. A thermal management system that is mounted on an electric vehicle and manages the heat of a heat medium circulating in a thermal circuit, a reservoir tank for temporarily storing the heat medium; a heating unit for electrically heating the heat medium to a boiling point; a heat exchanger for exchanging heat from the heated heat medium with the outside; a pump for pumping the heat transfer medium; Equipped with the heating unit is provided with a bubble discharge means for separating and discharging bubbles in the heat medium from the heat medium; A bubble collecting means is provided for collecting the bubbles discharged from the heating section. A thermal management system characterized by:

2. 2. The thermal management system of claim 1, The bubble discharge means has a structure that causes a spiral flow in the heating medium in a specific direction in the heating section. A thermal management system characterized by:

3. 3. The thermal management system according to claim 1, The bubble collecting means includes the reservoir tank and a bubble piping for flowing the bubbles from the heating unit to the reservoir tank. A thermal management system characterized by:

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